Glaucoma has been recognized as an infrequent but serious complication following surgery for congenital and acquired cataracts in childhood. Little is known concerning the influence of factors on the risk of glaucoma such as age at surgery, type of cataract, associated ocular abnormalities, and type of surgery. We reviewed records of 240 eyes of 155 patients on whom cataract surgery had been performed between January 1965 and July 1990 at Children's Hospital, Boston. After excluding those patients who had been followed up less than 5 years after surgery, and those who had had surgery after the age of 10 years, 125 eyes of 82 patients were included in the study group. We identified 14 eyes of 9 patients that had developed open-angle glaucoma 5.3 to 13.1 years following surgery (average 7.4 years). An additional 4 eyes of 3 patients developed angle closure glaucoma, which was diagnosed at 146, 177, 2911, and 2939 days following surgery. A fifth patient developed acute angle closure 1.7 years following primary cataract surgery and 53 days following secondary discission. All but one of the patients who developed glaucoma had cataract surgery at less than 1 year of age. Age at surgery for the entire study group averaged 1.9 years, and ranged from 25 days to 9.6 years. We conclude that patients having cataract surgery before 1 year of age are at the greatest risk of developing postoperative open-angle glaucoma. Additional increased relative risk was found in eyes with microcornea, congenital rubella syndrome, and poor pupillary dilation with 1% cyclopentolate (Cyclogyl). No significant difference was seen among the various surgical methods of cataract removal.